This invention relates to a controllable semiconductor component comprising a body of doped semiconductor material, two separate electrodes, each of which contacts the doped semiconductor material of the body and between which an electric operating voltage of the component is to be applied, and a control electrode which is insulated from the semiconductor material of the body by electrically insulating material and to which an electric control voltage is to be applied for controlling the component.
A known example of a component of this type is a unipolar MOS transistor, where the body is known to be made of at least one type of conduction in which one of the two electrodes is a drain electrode, and the other electrode is a source electrode, in which the drain electrode and the source electrode are each in contact with semiconductor material of the same type of conduction as the body, and the control electrode is a gate electrode extending over a doped MOS channel and a doped region adjacent to this channel and opposite from this channel, both being formed of semiconductor material in the body.
One example of such a MOS transistor is known from International Patent Application WO 98/02925. The particular feature of this transistor is that there is also another electrode in addition to the drain electrode, the source electrode and the gate electrode, this additional electrode being situated at a distance laterally from the gate electrode and separated from the semiconductor material of the body by electrically insulating material, and either connected to the source electrode or acted upon by its electric potential.
The additional electrode ensures a comparatively homogeneous field distribution in the edge area of the gate electrode and thus prevents the electric field strength in the semiconductor material from reaching a critical value of approximately 105 V/cm, which would trigger surge ionization and thus electron multiplication.
Another known example of a component of this type is a bipolar IGBT (=isolated gate bipolar transistor) in which the body is known to consist of semiconductor material of different types of conduction, whereby one of the two electrodes is an anode and the other electrode is a cathode; in which the electrode is in contact with the semiconductor material of the type of conduction of the body; in which the cathode is in contact with the semiconductor material of the type of conduction opposite the one type of conduction and/or the same type of conduction of the body; and in which the control electrode is also designated as a gate electrode.